Scientists have done the paleontological
equivalent of jamming a thermometer
up a giant reptile’s rear end. Reporting
online June 23 in Science, researchers say the huge, four-legged dinosaurs
known as sauropods would have registered a body temperature similar to that
of any modern Homo sapiens.

The work provides perhaps the best
glimpse yet at dinosaurs’ internal temperature, a key factor in understanding their
metabolism. The findings measure some
4 to 7 degrees Celsius cooler than one
theory of dinosaur growth has suggested.

Once thought to be cold-blooded and

Female infidelity may be inheritedHints of ‘cheating gene’ passed down by philandering dads

By Susan Milius

A study of infidelity among hundreds
of captive zebra finches shows that
philandering tendencies can be in part
inherited, says Wolfgang Forstmeier of
the Max Planck Institute for Ornithology in Seewiesen, Germany. The study
also reveals a partial link between male
and female philandering genes that

may help explain how female infidelity
evolves, Forstmeier and his colleagues
say online June 13 in the Proceedings of
the National Academy of Sciences.

Just why infidelity arises in females
of apparently monogamous species
has ruffled feathers among biologists
for years. Philandering by males is easy
to explain: More quick flutters in the
shrubbery mean more offspring in the
next generation. But that explanation
doesn’t work so well for females: They
often produce the same number of
youngsters regardless of whether there’s
one father or a dozen.

An idea proposed 24 years ago suggests

The benefits of infidelity for male zebrafinches (left) might favor genes that canmake a female (right) stray too, even ifit lends her no reproductive advantage.

Tallying bonds between certain oxygenand carbon atoms in this fossilized toothhelped determine the body temperatureof a dinosaur called Camarasaurus.

1 cm

in between 36° and 38° Celsius. That’s
warmer than cold-blooded creatures like
crocodiles, cooler than birds, and just
about the range of modern mammals.

Other scientists have suggested that
sauropod body temperature could have
reached 40° or even higher, simply
because of the sheer amount of the dinosaurs’ flesh. The new work fits with other
recent evidence suggesting that sauropods and modern mammals were about
the same temperature, says Luis Chiappe,
a paleontologist at the Natural History
Museum of Los Angeles County.

that there doesn’t have to be any benefit
to philandering females. They may simply inherit “cheating genes” that arose
among male ancestors who did benefit
by playing the field.

Testing the idea has been very difficult
since doing a proper experiment requires
knowing an awful lot about animals’
private lives. Researchers filmed and
monitored paternity for five generations
of birds, for a total of 800 males and 754
females. The researchers switched many
of the chicks from their original nests and
determined that nature, not nurture, was
influencing finch sexual behavior. And
the scientists painstakingly documented
who mated with or rebuffed whom.

The new finch study “is very, very
good,” says evolutionary biologist David
Westneat of the University of Kentucky
in Lexington. “I am still a bit skeptical
that this will be of widespread importance, but we definitely need to consider
this hypothesis about genetic correlations more seriously than before.”